One reason we're addicted to science fiction and fantasy: the characters and their weird, conflicted relationships. And there's nothing more addictive than characters who can't decide whether to kill each other or run away together. Friends who sometimes hate each other, or enemies who secretly admire each other.

Here are 10 of the most addictive love-hate relationships in science fiction and fantasy.

10) The Doctor and the Master, Doctor Who
What is the deal with the Doctor and the Master? They're both Time Lords from the planet Gallifrey, and they both went to the Academy together, but is that all there is to it? It's been hinted that they're brothers, but we'll probably never know. One thing is for sure, though — the Master keeps trying to kill the Doctor, but his heart never seems to be in it. And they enjoy dueling and outwitting each other and bantering far too much. Plus, the Doctor loves to float around and forgive the Master for everything.

9) Buffy and Faith, Buffy the Vampire Slayer
A bunch of people at Facebook suggested Buffy and Spike — but the Buffy/Faith relationship is even more fascinating. Buffy and Faith are equals, who both have Slayer powers and who serve as each other's foils on many occasions. Buffy and Faith almost become best friends a couple times, but they always end up butting heads. But every time it seems like they're about to become out-and-out enemies, they rediscover their mutual respect.

8) Lededje and Falling Outside the Normal Moral Constraints, Surface Detail by Iain M. Banks
After a slave named Lededje is murdered by her master, she's surprised to find herself alive once again, aboard the Culture Abominator-class ship Falling Outside the Normal Moral Constraints. But even though the warship has saved her life, she doesn't have the smoothest relationship with it — for one thing, the ship is always trying to control her. For another, the ship is pretty obsessed with its role as intimidating, unstoppable warship. "You'd make a great teenage boy," she tells its avatar at one point.

7) Odo and Quark, Star Trek: Deep Space Nine
Odo and Quark are the most stable pairing of DS9, a long-term marriage of strict lawfulness and rampant venality. Odo has been the security chief on board the station since before the Federation took it over, and all along he's been trying to curb Quark's criminal behavior. The two of them will never admit how much they secretly like each other, even as Odo is constantly trying to lock Quark up — and sometimes even succeeding. But DS9 is full of weird ambivalent relationships. See also: Dukat and practically everyone.

6) Rimmer and Lister, Red Dwarf
When Arnold Rimmer was alive, he and Lister didn't really get along — but now that Rimmer's been brought back to life as a hologram, he and Lister are tied together. And even though Rimmer's just as obnoxious as ever, he sort of grows on you over time. And you can tell there's oodles of romantic tension between the two roommates, by the copious amounts of Rimmer/Lister slash fiction all over the internet.

5) Spike and Faye, from Cowboy Bebop
Faye meets Spike Spiegel when she cheats him out of all his money at a poker table, and then Spike handcuffs her to the toilet. That's the beginning of a thorny relationship, in which the gambler becomes a valued but often annoying member of the Bebop crew. And over time, she seems to develop feelings for Spike — but does he reciprocate? The debate rages on.

4) Jaime and Brienne, A Song of Ice and Fire
It's a lot easier to name conflicted, troubled relationships than it is to think of straightforward, healthy ones in George R.R. Martin's brain-eating book series. But Jaime Lannister, especially, seems to have only ambivalent relationships — including his weird, poisonous love affair with his sister Cersei, and his complicated bond with his brother Tyrion. But — spoiler alert! — Jaime's relationship with Brienne of Tarth might be the most conflicted — he mocks her, and in return she scorns the Kingslayer. But they also seem to develop a weird respect for each other, and Jaime gives her the means to save her honor — and maybe his own, too. We can't wait to see this relationship play out on the TV show. Image by Motodraconis on DeviantArt.

3) Mal and Inara, Firefly
Inara saves Mal Reynolds' bacon a few times, and her business as a Companion goes a long way towards keeping the Serenity flying. But he's constantly needling her about her line of work, and she disapproves of some of his shady dealings. And yet, they also seem to have scorching romantic chemistry, and Inara can't resist the famous Mal Reynolds dimples. In the movie Serenity, Mal tells Inara, "You fog things up! You always have. You spin me about." Probably in season five or six of Firefly, those two would have finally gotten together.

2) Avon and Blake, Blake's 7
Look at any list of great quotes from this classic dystopian space opera, and fully half of them will probably feature Avon directing barbs at the "fearless leader" of this crew of rebels and criminals. Avon, the cynical computer expert, keeps trying to leave Blake for dead. He keeps trying to betray Blake — but somehow, he always comes through for Blake in the end. And even though Avon says he'll do anything to be free of Blake, he obviously has a deep admiration of the idealistic hero. And for his part, Blake tells Avon he's always trusted him, from the very beginning.

1) Han and Leia, Star Wars
No romantic relationship is spikier than that between Her Royal Highness and the Scruffy Nerf Herder. Han is such a scoundrel — why can't he be nice and well behaved, like that nice Luke kid? But somehow, the two of them keep finding themselves drawn together, and Han is always awesome when it counts. The tension just builds, from ice planet to asteroid field to Cloud City, until finally we get one of the most memorable exchanges: "I love you." "I know." And then she's willing to cross the galaxy and disguise herself in a totally ninjatastic bounty hunter outfit to save him.